Filter pad



April 30, 1946. I J. w, RM LY 2,399,158

FILTER PAD Filed May 18, 1944 gimme/whom Patented Apr. 30, 1946 UNITED STATES PATENT OFFICE FILTER PAD John Wadie Armaly, Detroit, Mich.

Application May 18, 1944, Serial No. 536,185

2 Claims.

This invention relates to filter pads for use in feed water boxes to remove oil and other foreign matter from the feed water before entering the boilers.

It has been customary for many years to supply boiler feed water systems with boxes in which loofa sponges are packed to filter out oil and other foreign matter to prevent these substances from entering and clogging or injuring the boiler tubes. As, at the present time, loofa sponges have become difficult to obtain in sufilcient quantities to supply the demand, it ha become imperative that some other means be found that can be used.

The object of the present invention is to provide a pad having a porous casing and fibrous filling capable of abstracting foreign material from water.

Another object of the invention is to provide such a filter pad which resists deterioration when subjected to water over lOl'lg periods of time.

A further object of the invention is to provide filter pads of such shape that they may be readily packed in feed water boxes in such manner as to fill up all cracks and present a substantially uniform and continuous filtering surface.

Other objects of the invention will be apparent from the following description taken in conjunction with the drawing which accompanies and forms a part of this specification, and throughout the several figures of which like ref erence characters indicate like parts.

In the drawing:

Figure 1 is a plan view of a filter pad embodying the principles of the present invention; and,

Figure 2 is a longitudinal cross section.

Figure 3 is a vertical section through a container with a plurality of the filter pads in position therein.

Referring to the drawing in detail, the filter Dad comprises a casing or cover I which is filled with a fibrous material 2.

The cover or bag I is of linoweave mesh construction, preferabl made of cotton specially selected to withstand the high heat and pressure conditions to which a filter pad of this character is subjected. The particular weave employed produces a definite open-mesh material which will permit the free flow of water to the interior of the bag. The bag is formed from a rectangular piece of'the material, folded upon itself and stitched along one transverse edge and its longitudinal edge. After the bag is filled with fibrous material, the remaining transverse edge is stitched to close the bag.

It is preferable that the filling material be sisal hemp. .The sisal may be of a low grade and may even include some portions which have heretofore been waste; No particular arrangement of the sisal is contemplated, the fiber merely being stuffed into the bag. in a rather loose manner.

It is of the utmost importance that the pad be absolutely clean and free from any small particles that might sift through the bag and get into the feed water lines. For this reason, the sisal is subjected to a cleaning process which removes all dirt and foreign matter which it may contain. This is done before the sisal is packe in the bags.

The pad when completed has a pillow-like appearance, and is readily compressible. The pads are of any convenient size, taper in thickness from their edge to the center and are adaptable to being placed in the feed boxes in overlapping position to completely cover the box. Of course, any number of layers may be used to build up the desired thickness.

Experiments with pads of this character have demonstrated that sisal filled filter pads will give more satisfactory results than do loofa sponges. These pads will remove more of the foreign matter from the water, they have a longer life, and they pack better in the feed water boxes. The only apparent sign of use after extended periods in the feed water box is the somewhat compressed condition of the pad due to the heavy pressure and volume of water.

While in the above a preferred and practical embodiment of the invention has been shown, changes from the precise form shown may be made within the scope of the appended claims.

What I claim is:

1. A filter pad element consisting of a rectangular outer casing of a heat resisting linoweave mesh fabric, and a filling of sisal fibers, the amount of filling being sufficient to give the pad a pillow-like shape tapering from the edges toward the center.

2. A filter bed comprising a plurality of filter pad elements, rectangular in shape and each tapering in thickness from its edges to the center, said elements arranged in overlapping relationship to form a bed of substantially uniform thickness throughout.

JOHN WADIE ARMALY. 

